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I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n

ITU-T

G.107

TELECOMMUNICATION

(12/2011)

STANDARDIZATION SECTOR

 

OF ITU

 

SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS

International telephone connections and circuits – Transmission planning and the E-model

The E-model: a computational model for use in transmission planning

Recommendation ITU-T G.107

ITU-T G-SERIES RECOMMENDATIONS

TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS

INTERNATIONAL TELEPHONE CONNECTIONS AND CIRCUITS

G.100–G.199

Transmission planning and the E-model

G.100–G.109

General Recommendations on the transmission quality for an entire international telephone

G.110–G.119

connection

 

General characteristics of national systems forming part of international connections

G.120–G.129

General characteristics of the 4-wire chain formed by the international circuits and national

G.130–G.139

extension circuits

 

General characteristics of the 4-wire chain of international circuits; international transit

G.140–G.149

General characteristics of international telephone circuits and national extension circuits

G.150–G.159

Apparatus associated with long-distance telephone circuits

G.160–G.169

Transmission plan aspects of special circuits and connections using the international telephone

G.170–G.179

connection network

 

Protection and restoration of transmission systems

G.180–G.189

Software tools for transmission systems

G.190–G.199

GENERAL CHARACTERISTICS COMMON TO ALL ANALOGUE CARRIER-

G.200–G.299

TRANSMISSION SYSTEMS

 

INDIVIDUAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE

G.300–G.399

SYSTEMS ON METALLIC LINES

 

GENERAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS

G.400–G.449

ON RADIO-RELAY OR SATELLITE LINKS AND INTERCONNECTION WITH METALLIC

 

LINES

 

COORDINATION OF RADIOTELEPHONY AND LINE TELEPHONY

G.450–G.499

TRANSMISSION MEDIA AND OPTICAL SYSTEMS CHARACTERISTICS

G.600–G.699

DIGITAL TERMINAL EQUIPMENTS

G.700–G.799

DIGITAL NETWORKS

G.800–G.899

DIGITAL SECTIONS AND DIGITAL LINE SYSTEM

G.900–G.999

MULTIMEDIA QUALITY OF SERVICE AND PERFORMANCE – GENERIC AND USER-

G.1000–G.1999

RELATED ASPECTS

 

TRANSMISSION MEDIA CHARACTERISTICS

G.6000–G.6999

DATA OVER TRANSPORT – GENERIC ASPECTS

G.7000–G.7999

PACKET OVER TRANSPORT ASPECTS

G.8000–G.8999

ACCESS NETWORKS

G.9000–G.9999

 

 

 

 

For further details, please refer to the list of ITU-T Recommendations.

Recommendation ITU-T G.107

The E-model: a computational model for use in transmission planning

Summary

Recommendation ITU-T G.107 gives the algorithm for the so-called E-model as the common ITU-T transmission rating model. This computational model can be useful to transmission planners, to help ensure that users will be satisfied with end-to-end transmission performance. The primary output of the model is a scalar rating of transmission quality. A major feature of this model is the use of transmission impairment factors that reflect the effects of modern signal processing devices.

In the 2000 version of this Recommendation, an enhanced version of the E-model was provided in order to better take into account the effects of room noise at the send side, and quantizing distortion. With the 2002 version, the impairment due to random packet loss was included in a parametric way for different codecs. Since the 2003 version, an enhanced modelling of quality in case of low talker sidetone levels is provided. The 2005 version enabled more accurate quality predictions for codecs under (short-term) dependent packet loss. The 2009 version included an Appendix II describing a provisional impairment factor framework for wideband speech transmission. This Appendix has now been updated, in favour of a new Recommendation ITU-T G.107.1. A reference implementation is given in Appendix III.

The online version of this Recommendation includes an electronic attachment containing a reference implementation of the E-Model in PHP4 scripting language. This electronic attachment is available free of charge on the ITU publications website at http://www.itu.int/rec/T-REC-G.107.

History

Edition

Recommendation

Approval

Study Group

1.0

ITU-T G.107

1998-12-03

12

2.0

ITU-T G.107

2000-05-18

12

3.0

ITU-T G.107

2002-07-14

12

4.0

ITU-T G.107

2003-03-16

12

5.0

ITU-T G.107

2005-03-01

12

5.1

ITU-T G.107 (2005) Amd. 1

2006-06-13

12

6.0

ITU-T G.107

2008-08-29

12

7.0

ITU-T G.107

2009-04-29

12

 

 

 

 

8.0

ITU-T G.107

2011-12-14

12

 

 

 

 

Rec. ITU-T G.107 (12/2011)

i

FOREWORD

The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis.

The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics.

The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1.

In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC.

NOTE

In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency.

Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party.

INTELLECTUAL PROPERTY RIGHTS

ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process.

As of the date of approval of this Recommendation, ITU had received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at http://www.itu.int/ITU-T/ipr/.

ITU 2012

All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU.

ii

Rec. ITU-T G.107 (12/2011)

 

 

Table of Contents

 

 

 

 

Page

1

Scope

............................................................................................................................

1

2

References.....................................................................................................................

1

3

Definitions ....................................................................................................................

2

4

Abbreviations ........................................................................................and acronyms

2

5

Conventions ..................................................................................................................

2

6

The E- ......................model, a computational model for use in transmission planning

2

 

6.1 ....................................................................................................

Introduction

2

 

6.2 ....................................................................................................

Source code

3

7

Structure .............................................................and basic algorithms of the E-model

3

 

7.1 .............................................

Calculation of the transmission rating factor, R

4

 

7.2 .......................................................................

Basic signal - to - noise ratio, Ro

4

 

7.3 ................................................................

Simultaneous impairment factor, Is

5

 

7.4 ...........................................................................

Delay impairment factor, Id

6

 

7.5 ....................................................................

Equipment impairment factor, Ie

7

 

7.6 ........................................................................................

Advantage factor, A

8

 

7.7 .................................................................................................

Default values

8

Annex A – Conditions ...........................................................................of using the E-model

10

 

A.1

Examples of conditions where caution must be exercised when using the

 

 

..........................................................................................................

E - model

10

 

A.2

Conditions for which the performance of the E - model has been improved

 

 

..............................................................

by updating from the earlier version

11

Annex B – Quality ..........................measures derived from the transmission rating factor R

13

Appendix I – ..............................................................Calculation of R from MOSCQE values

15

Appendix II – Provisional impairment factor framework for wideband speech

 

 

transmission ..................................................................................................................

16

Appendix III ...........................– Reference implementation of the E-model in ITU-T G.107

17

Bibliography.............................................................................................................................

 

18

Electronic attachment: Reference implementation of the E-model in PHP4 scripting language.

Rec. ITU-T G.107 (12/2011)

iii

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